Friday, June 22, 2007

False positives

GMailGMail has typically been good at keeping spam out of my inbox, and even the false positive rate has been amazingly good. So good, in fact, that I've mostly stopped scanning my spam folder for false positives.

Recently though I started wondering why I would see responses to messages I've never seen and if there's something wrong with commit and other notifications occasionally getting lost. Digging deeper I realized that GMail has started to flag a considerable portion of my legitimate email as spam. The false positive rate seems to be something like 8%. And it's not just random commit notifications that get lost, for example these messages got marked as spam!

I've now explicitly marked all false positives as "Not spam", and I really hope that the GMail spam algorithm learns something from this.


  1. Same here. I hadn't looked in the spam folder for ages and now I'm starting to find false positives showing up there. The pain being that so much goes in there that the thought of looking in there again to make sure no spam shows up is very painful :) I no longer have that time, it was reassigned elsewhere.

  2. That's disturbing. I have 40 thousand emails in my GMail spam folder. A new one arrives approximately once per minute. I simply *cannot* check for false positives. I hate spammers for taking a brilliant, world-changing communications technology and rendering it unreliable.

    PS: The font size on this website is ridiculously small, particularly the textarea which would be completely unreadable if it were any smaller. What is wrong with 100%/1em?

  3. The false positive rate seems to be back down now that I explicitly marked the incorrectly labelled messages as "Not spam", so apparently the spam algorithm learns or then the problem was just some temporary glitch in Gmail.